Telephone hold button
Posted on Jan 10, 2013
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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This interface circuit provides electrically isolated RS422 communication interface to the PC...
This project describes a new economical solution of home light control systems. The presented...
A gate voltage is applied to initiate the proceedings. When the gate voltage is in the ON state, Q
This circuit uses a timer to generate pulses at a 5-ms clock rate. The pulses are shifted into...
Running from a 9-V battery, this transmitter can be used as a wireless microphone with an...
The above circuit will charge any 2-cell * Li-Ion battery pack. Maximum current is about 650...
This circuit is designed to create an early warning alarm system for any form of theft that are...
A very simple 10 LED roulette wheel circuit is shown here. pressing the button starts the LEDs in...
A total of six buffer circuits (using three dual op-amp packages), five for the input channels...
The preamplifier offers 20dB in all the region of VHF and it still can reach also their 500MHZ....
This simple circuit drives 6 LEDs in `Knightrider scanner mode`. Power consumption depends mainly...
This characterization circuit, plus a PC and some software, accurately measures the full...
The job of this timer is to disconnect thecompressor circuit and connect a resistive...
Low-drain circuit operating from 1. 5-V cell uses National LM3909 flasher ICs to simulate...
DC voltage present on the telephone line is usually about 45 to 50V, on-hook and off-hook to 6V....
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